Prazosin Pharmacology

Prazosin

About Prazosin
Selective alpha-1 adrenergic blocker, a quinazoline derivative, Antihypertensive.
Mechanism of Action of Prazosin
The drug exerts its antihypertensive action by acting as a selective alpha-1 antagonist. It dilates both arteries and veins, thus it reduces total peripheral resistance, reduce blood pressure, & reduce venous return and cardiac output. It decreases central sympathetic outflow. The drug also reduces the tone of the internal sphincter of the bladder thus decrease the resistance to urinary outflow in patients with benign prostatic hypertrophy. It decrease the tone of prostatic and bladder neck muscles and relaxes bladder trigone, prostate, and prostatic urethra; reduces dynamic obstruction, increases urinary flow rate, causing more complete emptying of bladder. The drug decreases LDL cholesterol & increases HDL cholesterol.
Pharmacokinets of Prazosin
Absorption: It is absorbed orally up to 60%. Distribution: Widely distributed in a highly plasma protein bound form, Metabolism: It is metabolized in liver,
Excretion: Excreted mainly through bile
Onset of Action for Prazosin
2 to 3minuts
Duration of Action for Prazosin
12 hours
Half Life of Prazosin
3hours
Side Effects of Prazosin
1.Postural hypotension
2.Headache
3.Drowsiness
4.Dizziness
5.Dryness of mouth
6.Nasal congestion
7.Rash
8.Blurred vision
9.Palpitation
10.Weakness
11.Impairment of ejaculation in males
12.Fluid retention


Contra-indications of Prazosin
1.Hypersensitivity to the drug
2.CHF due to mechanical obstruction
Special Precautions while taking Prazosin
1.Angina pectoris
2.Renal impairment
3.Hepatic impairment
4.Phaeochromocytoma
5.To avoid withdrawal syndrome gradually withdraw with caution
6.Use with caution along with other anti hypertensive drugs
7.Started with low dose usually given at bed time
Pregnancy Related Information
Use with caution
Old Age Related Information
Use with caution
Breast Feeding Related Information
Use with caution
Children Related Information
Use with caution
Indications for Prazosin
1.Hypertension
2.Benign prostatic hypertrophy
3.Left ventricular failure not controlled by digitalis & diuretics
Interactions for Prazosin
Clonidine: Antihypertensive effect of clonidine may be decreased.
Beta-adrenergic blocking agents: May enchance "first dose" acute postural hypotension of prazosin.
Indomethacin: Antihypertensive effect of prazosin decreased.
Verapamil & Nifedipine: Acute hypotensive effect when coadministered with prazosin.
Lab tests: False positive results may occur in screening tests for phaeochromocytoma in patients receiving prazosin.
Typical Dosage for Prazosin
Hypertension: Starts with 500mcg at bed time, Then 500mcg 12th hourly or 8th hourly in first week & 1mg 12th hourly or 8th hourly in second week. Dose gradually increases up to 20mg/day in divided doses if required.
Benign prostatic hypertrophy: Starts with 500mcg at bed time. Then 500mcg 12th hourly in first week. Dose gradually increases up to 1 to 3 mg 12th hourly

Schedule of Prazosin
H
Storage Requirements for Prazosin
Store at room temperature in a light resistant tightly closed container
Effects of Missed Dosage of Prazosin
Take the missed dose as soon as noticed and if it is the time for next dose then skip the missed dose. Continue the regular schedule. Do not double the dose.
Effects of Overdose of Prazosin
Treatment is supportive and symptomatic. After ingestion empty the stomach by induced emesis and gastric lavage. Administer activated charcoal.

Home Delivery for Prazosin in Your City

Medicine India is just a publishing medium for medicine related information and does not provide services or sales of medicines including prazosin.

However, we do publish a comprehensive directory of Pharmacies, Chemists and Druggists in cities all over India. You can use this directory to find the medicine stores in your city (or area) that provide home delivery services for prazosin and other medicines and health products. Home delivery services for prazosin may be free or they may cost you depending on the pharmacy and the minimum order requirements. It would be best to get this clarified while placing the order.

Please be aware that you should take prazosin only if a doctor has recommended or prescribed it. Some or all pharmacies who provide a home delivery service for medicines might insist on a prescription for prazosin before they complete the sale. You can get this information while placing the order for prazosin with the pharmacy.

Prazosin is a generic medicine name and there are several brands available for it. Some of the brands for prazosin might be better known than prazosin itself. If the pharmacy that's willing to deliver medicines to your home doesn't have prazosin in stock, you can ask for one of the branded alternatives for prazosin.